minio/cmd/config/bool-flag.go

/*
 * MinIO Cloud Storage, (C) 2017-2019 MinIO, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package config

import (
	"encoding/json"
	"fmt"
	"strconv"
	"strings"
)

// BoolFlag - wrapper bool type.
type BoolFlag bool

// String - returns string of BoolFlag.
func (bf BoolFlag) String() string {
	if bf {
		return "on"
	}

	return "off"
}

// MarshalJSON - converts BoolFlag into JSON data.
func (bf BoolFlag) MarshalJSON() ([]byte, error) {
	return json.Marshal(bf.String())
}

// UnmarshalJSON - parses given data into BoolFlag.
func (bf *BoolFlag) UnmarshalJSON(data []byte) (err error) {
	var s string
	if err = json.Unmarshal(data, &s); err == nil {
		b := BoolFlag(true)
		if s == "" {
			// Empty string is treated as valid.
			*bf = b
		} else if b, err = ParseBoolFlag(s); err == nil {
			*bf = b
		}
	}

	return err
}

// FormatBool prints stringified version of boolean.
func FormatBool(b bool) string {
	if b {
		return "on"
	}
	return "off"
}

// ParseBool returns the boolean value represented by the string.
// It accepts 1, t, T, TRUE, true, True, 0, f, F, FALSE, false, False.
// Any other value returns an error.
func ParseBool(str string) (bool, error) {
	switch str {
	case "1", "t", "T", "true", "TRUE", "True", "on", "ON", "On":
		return true, nil
	case "0", "f", "F", "false", "FALSE", "False", "off", "OFF", "Off":
		return false, nil
	}
	if strings.EqualFold(str, "enabled") {
		return true, nil
	}
	if strings.EqualFold(str, "disabled") {
		return false, nil
	}
	return false, fmt.Errorf("ParseBool: parsing '%s': %s", str, strconv.ErrSyntax)
}

// ParseBoolFlag - parses string into BoolFlag.
func ParseBoolFlag(s string) (bf BoolFlag, err error) {
	b, err := ParseBool(s)
	return BoolFlag(b), err
}